1. Field of the Invention
The invention relates to a connector to be mounted on an electric or electronic device, such as a circuit board connector.
2. Description of the Related Art
Japanese Unexamined Utility Model Publication No. S61-60486 discloses a circuit board connector with a housing that is connectable with a mating connector. Terminal fittings penetrate the back wall of the housing so that front parts of the terminal fittings project inside the housing and rear parts are exposed outside the housing. The rear parts are bent towards a circuit board and rear ends of the terminal fittings are soldered to the circuit board.
Fixing portions bulge out at the bottom ends of the opposite side surfaces of the housing and screws are driven into internally threaded holes in the fixing portions to fix the housing to the circuit board. The fixing portions must have sufficient strength to bear a screw driving force, and hence the fixing portions tend to be large.
Consideration has been given to forming the fixing portions of metal and then soldering the metal fixing portions the circuit board. The metal fixing portions then could be smaller. However, reflow soldering generates significant heat and causes the entire housing to expand thermally. Thus, a separating force acts on the fixing portions in a direction away from the circuit board and could cause the fixing portions to become unsoldered. Lead-free solder has become widely used for environmental reasons. However, lead free solder has a high melting point and requires the housing to pass through a reflow furnace for a long time at high temperatures. Therefore, the influence of the thermal expansion of the housing on the fixing portions cannot be ignored.
The invention was developed in view of the above problem, and an object thereof is to satisfactorily keep a connected state of fixing portions.